Sideloading is basically installing certain applications that are not available on app galleries such as Google Play Store or Apple App Store via third-party sources. Current and newer Huawei devices rely on HMS (Huawei Mobile Services) app gallery, which does not feature Google applications due to the ban imposed by the US government.
Ostrovski did not imply that Huawei devices are unsafe, but expresses concern that sideloaded Google apps are not accessible to the company’s Play Protect service. The service provides baseline protection against malware, privacy hacks, and so on to certified applications, but is not available on the devices by the Chinese tech giant. On the other hand, the blog post also states that Google will still provide support for Huawei phones released before the 16 May 2019 ban. Security updates and other services will proceed as usual for devices such as the P30 series, Y9, and other older models by the company. (Source: Google via Android Authority.)
